A cross section of the skull shows foramina, which are numerous canals passing through the bones of the skull. Through these channels blood vessels and 24 cranial nerves (12 on each side) enter and exit the intracranial cavity.
Other smaller channels connect the external veins of the skull with the internal ones. They are called connecting, or drainage, veins. Through such channels, an infection that originates outside the skull can get inside it and turn into serious inflammation.
The most important cranial foramina are:
- foramen magnum, connects the spinal cord with its trunk;
- torn hole located between rocky part temporal bone and sphenoid bone;
- oval foramen through which the maxillary branch passes trigeminal nerve;
- foramen spinosum, allows the median artery meninges penetrate into the cranial cavity;
- stylomastoid foramen - canal of the seventh cranial nerve;
- jugular foramen, which provides access to the sigmoid and inferior petrosal sinuses;
- the canal of the carotid artery through which the artery and its associated nerve fibers pass.
| Holes | Through the holes pass | ||||
| arteries | veins | nerves | |||
| Front cranial fossa | |||||
| Lattice holes | Anterior ethmoidal - branch of the ophthalmic artery | Ethmoidal (drains into the superior ophthalmic vein) | Olfactory nerves | ||
| Middle cranial fossa | |||||
| Visual channel | Ophthalmic | Optic nerve | |||
| Upper orbital fissure | Anterior meningeal branch - branch of the anterior ethmoidal artery | Superior ophthalmic (empties into cavernous sinus) | Oculomotor, trochlear, abducens nerves, optic nerve- first branch | ||
| Internal aperture of the carotid canal | Internal sleepy | Venous plexus of the carotid canal | Internal carotid (sympathetic) plexus | ||
| Round hole | - | - | Maxillary - second branch of the trigeminal nerve | ||
| Oval hole | Accessory branch of the middle meningeal artery | Venous plexus of the foramen ovale, connects the cavernous sinus and the pterygoid (venous) plexus | Mandibular - third branch of the trigeminal nerve | ||
| Foramen spinosum | Middle meningeal - branch of the maxillary artery | Middle meningeal | Meningeal branch of the maxillary nerve | ||
| Cleft canal of the greater petrosal nerve (canal opening facial nerve) | Petrosal branch - branch of the middle meningeal artery | Auditory (empties into the superior petrosal sinus) | Greater petrosal - branch of the facial (intermediate) nerve | ||
| Cleft of the lesser petrosal nerve canal (superior aperture of the tympanic tubule) | Superior tympanic - branch of the middle meningeal artery | – | Lesser petrosal - branch of the tympanic nerve (from the glossopharyngeal) | ||
| Posterior cranial fossa | |||||
| Interior ear canal | Labyrinthine artery - branch of the basilar artery | Veins of the labyrinth (drain into the inferior petrosal sinus) | Facial and vestibulocochlear | ||
| Aperture of the vestibular tubule | – | Endolymphatic duct and pouch | - | ||
| Cochlear tubule aperture | Perilymphatic duct (flows into the superior bulb of the internal jugular vein), vein of the tubule of the same name | ||||
| Mastoid | Meningeal branch of the occipital artery | Mastoid emissary (connects the sigmoid sinus and occipital vein) | |||
| Jugular | Posterior meningeal branch of the ascending pharyngeal artery | Internal jugular | Glossopharyngeal, vagal, extra nerves, meningeal branch of the abdominal nerve | ||
| Big | Vertebrates, anterior and posterior spinal cords | Basilar venous plexus | Medulla | ||
| Sublingual canal | – | Veins of the hypoglossal canal flow into the internal jugular vein | Hypoglossal nerve | ||
| Condylar canal | – | Condylar emissary (connects the sigmoid sinus with the vertebral venous plexus) | |||
The border between the anterior and middle fossae is
posterior edges of the lesser wings of the sphenoid bone,
between the middle and back - the upper edge of the pyramids temporal bones.
The anterior cranial fossa, fossa cranii anterior, is formed
1. orbital part of the frontal bone,
2. cribriform plate of the ethmoid bone and
3. small wings wedge-shaped.
The middle cranial fossa, fossa cranii media, lies deeper than the anterior one.
middle part The fossa is formed by the sella turcica.
The lateral parts include the large wings of the sphenoid bone, pars squamosa and the anterior surface of the pyramids of the temporal bones.
Middle fossa openings:
1. canalis opticus,
2. fissura orbitalis superior,
3. foramen rotundum,
4. foramen ovale,
5. foramen spinosum,
6. foramen lacerum.
The posterior cranial fossa, fossa cranii posterior, is the deepest and most voluminous.
It includes:
1. occipital bone,
2. posterior parts of the body of the sphenoid bone;
3. pars petrosa of the temporal bone and
4. inferior posterior corner of the parietal bone.
Openings of the posterior cranial fossa:
1. foramen magnum,
2. canalis hypoglossalis,
3. foramen jugulare,
4. canalis condylaris (sometimes absent),
5. foramen mastoideum (more permanent),
6. porus acusticus internus (on the back surface of the pyramid).
The internal auditory foramen (right and left) opens into the posterior cranial fossa on each side, leading into the internal auditory canal, in the depths of which the facial canal for the facial nerve (VII pair) originates. The vestibulocochlear nerve emerges from the internal auditory opening (VIII
pair).
Two more paired large formations: the jugular foramen, through which the glossopharyngeal (IX pair), vagus (X pair) and accessory (XI pair) nerves pass, and the hypoglossal canal for the nerve of the same name (XII pair)
Sleepy channel. Connects the outer base of the skull and the apex of the pyramid of the temporal bone. The channel contains an internal carotid artery, internal carotid plexus.
Musculo-tubal canal. Connects the apex of the temporal bone pyramid and the tympanic cavity. The canal contains muscles that tense eardrum, auditory tube.
Carotid tympanic tubules. Connect the carotid canal and the tympanic cavity. The canal contains the carotid-tympanic nerves and plexuses.
Internal auditory canal. Connects the posterior cranial fossa and inner ear. The canal contains the facial nerve, vestibulocochlear nerve, artery and vein inner ear.
Facial canal. Connects the posterior surface of the pyramid of the temporal bone and the stylomastoid foramen. The facial nerve passes through Canada.
Drum string channel. Connects the facial canal, the tympanic cavity and the petrotympanic fissure. In Canada there is a chorda tympani and a branch of the facial nerve.
Tympanic canaliculus. Connects the lower surface of the pyramid of the temporal bone, the tympanic cavity and the anterior surface of the pyramid. In Canada there is a branch of the glossopharyngeal nerve and the lesser stone nerve.
Mastoid canal. Connects the jugular fossa and the tympanomastoid fissure. The auricular branch of the vagus nerve passes through the canal.
Plumbing vestibule. Connects the vestibule of the inner ear and the posterior cranial fossa. The canal contains the aqueduct of the vestibule and the vein of the aqueduct of the vestibule.
snail plumbing. Connects the vestibule of the inner ear and the lower surface of the pyramid of the temporal bone. The canal contains the cochlear aqueduct and the cochlear canaliculus vein.
No. 10 Sphenoid bone: its parts, holes and their purpose.
Sphenoid bone,os sphenoidale, located in the center of the base of the skull. It participates in the formation of the lateral walls of the cranial vault, as well as the cavities and fossae of the cerebral and facial parts of the skull. The sphenoid bone has a complex shape and consists of a body from which 3 pairs of processes extend: large wings, small wings and pterygoid processes.
Body,corpus The sphenoid bone has the shape of an irregular cube. Inside it there is a cavity - the sphenoid sinus, sinus sphenoidalis. There are 6 surfaces in the body: the upper, or cerebral; posterior, fused in adults with the basilar (main) part of the occipital bone; the front one, which passes without sharp boundaries into the lower one, and two lateral ones.
Small wing, ala minor, It is a paired plate extending from each side of the body of the sphenoid bone with two roots. Between the latter is the visual channel, canalis opticus, for the passage of the optic nerve from the orbit. The anterior edges of the lesser wings are serrated; the orbital parts of the frontal bone and the cribriform plate of the ethmoid bone are connected to them. The posterior edges of the small wings are free and smooth. On the medial side of each wing there is an anterior inclined process, processus clinoideus anterior. The dura mater of the brain grows to the anterior as well as to the posterior inclined processes.
The lesser wing has an upper surface facing the cranial cavity, and a lower one, participating in the formation of the upper wall of the orbit. The space between the lesser and greater wings is the superior orbital fissure, fissura orbitalis superior. The oculomotor, lateral and abducens nerves (III, IV, VI pairs) pass through it from the cranial cavity to the orbit cranial nerves) and the optic nerve - I branch of the trigeminal nerve (V pair).
Big wing, ala major, paired, begins with a wide base from the lateral surface of the body of the sphenoid bone (Fig. 32). At the very base, each wing has three holes. Above the others and in front there is a round hole, foramen rotundum, through which the second branch of the trigeminal nerve passes, in the middle of the wing there is the foramen ovale, foramen ovale, for the third branch of the trigeminal nerve. Foramen spinosum, foramen spinosum, smaller in size, located in the region of the posterior corner of the large wing. Through this opening, the middle meningeal artery enters the cranial cavity.
The large wing has four surfaces: medullary, orbital, maxillary and temporal. On the surface of the brain fades cerebralis, finger-shaped impressions are well defined, impressidnes digitatae, and arterial grooves, sulci arteriosi. orbital surface, fades orbitalis,- quadrangular smooth plate; part of the lateral wall of the orbit. maxillary surface, fades maxillaris, occupies a plot triangular shape between the orbital surface above and the base of the pterygoid process below. On this surface, facing the pterygopalatine fossa, a round opening opens. Temporal surface, fades tempordlis, the most extensive. infratemporal crest, crista infratemporalis, divides it into two parts. Top part larger in size, located almost vertically, part of the wall of the temporal fossa. The lower part is located almost horizontally and forms the upper wall of the infratemporal fossa.
pterygoid process,processus pterygoideus, paired, departs from the body of the sphenoid bone at the beginning of the large wing and is directed vertically downward. The medial plate of the process faces the nasal cavity, the lateral plate faces the infratemporal fossa. The base of the process is pierced from front to back by a narrow pterygoid canal, canalis pterygoideus, in which blood vessels and nerves pass. The anterior opening of this canal opens into the pterygopalatine fossa, the posterior one - on the outer base of the skull near the spine of the sphenoid bone, splna ossis sphenoidalis. The plates of the pterygoid process are distinguished: medial, lamina medidlis, and lateral, lamina lateralis. The anterior plates are fused. Posteriorly, the plates of the pterygoid process diverge, forming the pterygoid fossa, fossa pterygoidea. At the bottom, both plates are separated by a pterygoid notch, incisura pterygoidea. The medial plate of the pterygoid process is somewhat narrower and longer than the lateral one and below passes into the pterygoid hook, Hamulus pterygoideus.
No. 11 Pterygopalatine fossa: its walls, openings and their purpose.
Pterygopalatine (pterygopalatine) fossa, fossa pterygopa-Iatina, has four walls: anterior, superior, posterior and medial. The anterior wall of the fossa is the tubercle of the maxilla, the upper wall is the inferolateral surface of the body and the base of the greater wing of the sphenoid bone, the posterior wall is the base of the pterygoid process of the sphenoid bone, the medial wall is the perpendicular plate of the palatine bone. On the lateral side, the pterygopalatine fossa does not have a bone wall and communicates with the infratemporal fossa. The pterygopalatine fossa gradually narrows downwards and passes into the greater palatine canal, canalis palatinus major, which at the top has the same walls as the fossa, and at the bottom it is delimited upper jaw(laterally) and palatine bone (medially). Five openings enter the pterygopalatine fossa. On the medial side, this fossa communicates with the nasal cavity through the sphenopalatine foramen, superiorly and posteriorly with the middle cranial fossa through the round foramen, posteriorly with the region of the foramen lacerum via the pterygoid canal, and inferiorly with the oral cavity through the greater palatine canal.
The pterygopalatine fossa is connected to the orbit through the inferior orbital fissure.
No. 12 Nasal cavity, the structure of its walls. Paranasal sinuses, their meaning, variants and anomalies.
nasal cavity, cavum nasi, occupies a central position in facial area skulls Bone septum of the nose, septum ndsi osseum, consisting of a perpendicular plate of the ethmoid bone and a vomer, fixed below on the nasal ridge, divides the bony cavity of the nose into two halves. In front, the nasal cavity opens with a pear-shaped aperture, apertura piriformis, limited by the nasal notches (right and left) of the maxillary bones and the lower edges of the nasal bones. In the lower part of the pyriform aperture, the anterior nasal spine protrudes forward, spina nasalis anterior. Through the posterior openings, or choanae, shoapae, The nasal cavity communicates with the pharyngeal cavity. Each choana is bounded on the lateral side by the medial plate of the pterygoid process, on the medial side by the vomer, above by the body of the sphenoid bone, and below by the horizontal plate of the palatine bone.
It consists of many elements (channels, grooves, surfaces, tubercles, etc.) and students of medical academies recall how they studied it at Latin language like a bad dream.
The temporal bone is located on the border between the cranial vault and the base of the skull. It is connected to almost all other bones of the skull different types connections. It contains the organs of balance (vestibular apparatus) and hearing (inner ear). Various muscles of the neck are attached to it from below, the carotid artery (internal branch) passes through it from the inside, and there is an auditory opening on its outside surface. These are not all the formations that the temporal bone has.
Temporal bone canals
The temporal bone contains several canals and tubules:
- carotid channel;
- carotid tubules;
- muscular-tubal canal;
- facial canal;
- tympanic tubule;
- drum string channel;
- mastoid tubule.
Each canal of the temporal bone contains a specific anatomical formation. Let's take a closer look at the anatomy of these channels.
Sleepy channel
This canal is named so because it contains the temporal part of the internal carotid artery. The carotid canal (in Latin canalis caroticus) originates from the bottom of the temporal bone with an external opening, passes through its thickness upward and then turns anteriorly almost at a right angle and ends in the cranial cavity. The ICA (internal carotid artery) supplies blood most brain. The carotid artery in the canal is accompanied by veins and a plexus of nerve fibers of the sympathetic nervous system.
Carotid tympanic tubules
In Latin - canaliculi caroticotympanici - they are two small tubules that branch from the carotid canal and lead into the tympanic cavity. These channels contain carotid-tympanic nerve fibers.
Musculo-tubal canal
In Latin - canalis musculotubarius. Originates from the anterior superior wall of the tympanic cavity. The entrance to the canal is located near the external auditory opening. Inside the channel itself there is a horizontal partition that divides it into two half-channels. The upper hemicanal contains a muscle that strains the eardrum. It is smaller relative to the lower one. The lower channel forms an anatomical connection between the pharyngeal cavity (atmospheric pressure) and the tympanic cavity to equalize air pressure across different sides eardrum. Thanks to this channel, we can always hear the same way even with different fluctuations in atmospheric pressure. On the other hand, inflammation of the mucous membrane of this canal can lead to inflammatory processes in the tympanic cavity.
Facial canal
The facial canal (in Latin canalis facialis) originates in the lower part of the internal auditory canal and runs horizontally. Inside the temporal bone, it turns at a right angle, forming the knee of the facial canal, and exits into the tympanic cavity. Having passed through the latter in a posterior direction, it turns down and exits onto the surface of the temporal bone, where it ends in an opening called the stylomastoid because of the proximity of the styloid and mastoid processes near it.
Drum string channel
In Latin - canaliculus chordae tympani. It originates from the facial canal near the stylomastoid foramen and ends in the tympanic cavity. The contents of this canal are the nerve that innervates the anterior two-thirds of the tongue (taste) and the salivary glands (sublingual and submandibular). This nerve is called the “cord of drums”.
Tympanic canaliculus
In Latin - canaliculus tympanicus. It originates on the surface of the temporal bone (its petrous part) and also leads into the tympanic cavity.
Mastoid tubule
In Latin - canaliculus mastoideus. It contains the auricular branch nervus vagus(nervus vagus). It begins in the jugular fossa and leads into the tympanomastoid fissure.
As you can see, the temporal bone is literally pitted with various canals, tubules, grooves and other anatomical formations. Especially if you take into account that its volume (the rocky part) is slightly larger than the volume of a matchbox. All this is due to the presence in the temporal bone of ultra-thin organs of hearing and coordination, which have rich innervation and blood supply.
Video: Temporal bone - Canals
Every bone human body is the most important “cog” in a huge mechanism. The head bone elements perform protective function. These elements include the temporal bone.
Temporal bone: description
An important part of the skull is the temporal bone, which is located on both sides of the skull, and therefore is a pair. More precisely, it belongs to one of the components of the skull that covers the brain. It is surrounded by the sphenoid, parietal and occipital bones.
This bone element in combination with lower jaw forms a movable joint. And in tandem they form the zygomatic arch.
The temporal element itself is not a single bone: it is represented by a number of parts that form it.
The temporal bone develops by ossification from six points. At the end of the 8th week of embryonic development, the scaly parts are the first to ossify. In the 3rd month, hardening occurs in the tympanic part. With the arrival of the 5th month of fetal development, several areas of ossification appear in the cartilaginous portion of the pyramid.
By the period preceding birth, the temporal bone already consists of a scaly part, a tympanic and a petrous part, and in between these parts there are clefts with connective tissue.
Bone structure
The anatomy of the temporal bone is as follows. It consists of a pyramid, a drum part and scales.
The pyramid is also called the rocky part. And for good reason, because this element consists of a very hard bone element. In its shape, the rocky part is very similar to a triangular pyramid (hence the name). The base of the pyramid extends into the mastoid process.
The pyramid consists of the following parts: the top; front, back and bottom surfaces; apical, posterior and inferior margins.
The frontal has an orientation expressed forward and upward. On the lateral side, the pyramid passes into the scales of the temporal bone. Between these two elements of the temporal bone is the petrosquamosal foramen. In its central part, the front surface of the pyramid has a small arched elevation. At a distance through these elevations, in the form of a scaly opening, there is a flat section that serves as the roof of the tympanic cavity.
The back surface of the pyramid is adjacent to the center. Almost in the central part of this surface of the pyramid there is a small auditory opening, which flows into the internal auditory canal. On the lateral side of the auditory opening is the subarcular fossa. And on the lower side there is a hole for the vestibule water supply.
The lower surface of the pyramid is equipped with a difficult surface relief. The lower surface flows into the mastoid process.
The upper edge of the pyramid is the boundary line connecting the front and back surfaces. At its base there is a groove for the petrosal sinus.
The posterior edge of the pyramid separates the posterior and inferior surfaces. Along its surface lies the groove of the inferior petrosal sinus. Near the side of the groove there is a dimple with the external opening of the cochlear canaliculus.
WITH inside the pyramid houses the organs of hearing and balancing.
The diagram shows:
Functions
The temporal bone has three functions:
- Protective. The temporal bone, together with the rest of the bones of the skull, protects the brain from various types of damage.
- Support. The cranial bone supports the brain, being its support.
- The temporal bone is the attachment point for the head muscles.
In addition, this bone contains organs and canals hearing aid, equilibrium, and also contains various tubules and vessels.
The functions performed depend entirely on the anatomy of the temporal bone. Additionally, the location of nearby bones also affects functionality.
Temporal bone canals
The temporal bone is completely striated with various notches, depressions and canaliculi. The canals and cavities of the temporal bone serve to conduct blood vessels, nerve branches, and arteries. The canals are hollow tubular cords that intertwine parts of the temporal bone.
Below is a table of the temporal bone canals.
| Bone canals | What cavities connect | What crosses the channels |
| Facial canal | Dorsal wall of the pyramid and stylomastoid foramen | 7th petrosal artery and stylomastoid vessels |
| Sleepy channel | Apex of the pyramid and outer base of the skull | Carotid artery and carotid plexus |
| Musculo-tubal canal | and the upper wall of the pyramid | Superior tympanic artery, auditory tube |
| Drum string channel | Facial canal, tympanic cavity and tympanic fissure | 7th facial nerve and posterior tympanic artery |
| Mastoid tubule | Jugular recess and mastoid fissure | auricular process of the 10th pulmonary gastric nerve |
| Tympanic canaliculus | Petrosal fossa, inferior wall of the pyramid and tympanic cavity | Lesser petrosal nerve vessel, tympanic artery, lying inferiorly |
| Carotid tympanic tubules | The edge of the carotid cord and the tympanic cavity | Carotid-tympanic nerve fibers and arteries |
| Snail tubule | The beginning of the internal auditory organ and the lower base of the pyramid | Cochlear canaliculus vein |
| Internal auditory canal | Inner ear and posterior cranial fossa | 7th facial nerve, 8th cochlear nerve and inner ear artery |
| Plumbing vestibule | The beginning of the inner ear and the cranial fossa located on the back side | Venous vessel of the aqueduct |
Facial nerve canal
Let's look at the facial canal of the temporal bone. It originates on the underside of the hearing aid, located inside the ear. Its direction is expressed laterally - forward to the cleft of the petrosal nerve fiber canal. In this area it forms a turn, which is called the elbow of the facial canal. The facial canal of the temporal bone continues its path from the knee in the direction of the side and back, along the trajectory of a right angle parallel to the axis of the pyramid. Then the direction becomes vertical and ends with the mastoid opening at the rear wall of the tympanic cavity.
Sleepy channel
The carotid canal of the temporal bone begins its journey on the underside of the pyramid in the form of a hole (aperture). Its direction is straight and upward, but closer to the surface of the pyramid. The canal bends at an angle of 90 and exits through the external opening at the apex of the pyramid. The carotid artery passes through the canal.
Musculo-tubal canal
The myotubal canal of the temporal bone is a fragment of the auditory tube of the inner ear. The canal begins at the apex of the pyramid, namely, located between its frontal edge and the scales of the temporal bone.
Drum string channel
This canaliculus begins from the canal of the facial nerve, but its beginning is located slightly higher from the stylomastoid foramen, and ends in the petrotympanic fissure. The contents of this temporal bone canal have been discussed in more detail in the table.
Mastoid tubule
The canaliculus originates in the jugular fossa, crosses the lower part of the facial canal and ends in the mastoid-tympanic fissure. The mastoid canal carries the process of the vagus nerve through its cavity.
Tympanic canaliculus
The tympanic tubule originates from the bottom of the stony fossa. It continues its path in an upward and straight direction. It crosses the section of the tympanic cavity located below and rushes to the top of the promontory, but in the form of a groove. Its end exits through the cleft of the petrosal nerve, located on the anterior side of the pyramid of the temporal bone.
The tympanic canal contains the tympanic nerve in its cavity.
Carotid tympanic tubules
There are two carotid tympanic tubules in total. They begin from the wall of the carotid canal, from where they are further discharged into the tympanic cavity. The function of these channels is conduction.
The canals of the temporal bone are shown schematically above. They show the complexity of the processes occurring in the bones.
The temporal bone is divided into the pyramid (stony part) with the mastoid process, the tympanic part, and the scaly part.
Pyramid, or the stony part is so called due to the hardness of its bone substance and has the shape of a triangular pyramid. Inside it is the organ of hearing and balance. The pyramid in the skull lies almost horizontal plane, its base is directed back and laterally and passes into the mastoid process.
Several channels of the temporal bone pass through the pyramid for cranial nerves and blood vessels.
Sleepy channel
The carotid canal (canalis caroticus) begins on the lower surface of the pyramid with the external carotid foramen, goes upward, bends almost at a right angle, then goes medially and forward. The canal ends with the internal carotid foramen at the top of the pyramid of the temporal bone. The internal carotid artery and the nerves of the carotid plexus pass through this canal into the cranial cavity.
The internal carotid artery, the internal carotid (autonomic) nerve plexus, passes through the carotid canal.
Carotid tympanic tubules
Carotid-tympanic tubules (canaliculi caroticotympanici), numbering 2-3, begin on the wall of the carotid canal (near its external opening) and penetrate into the tympanic cavity.
These tubules contain the carotid-tympanic nerves and arteries.
Musculo-tubal canal
The muscular-tubal canal (canalis musculotubularis) has a common wall with the carotid canal, begins at the apex of the pyramid of the temporal bone, goes backward and laterally and opens into the tympanic cavity.
It consists of two sections: the semicanal of the auditory tube (semicanalis tubae auditivae) and the semicanal of the tensor tympani muscle (semicanalis m. tensoris tympani). The upper hemicanal is occupied by the tensor tympani muscle, and the lower hemicanal is the bony part of the auditory tube. Both half-channels open into the tympanic cavity on its anterior wall.
A horizontal partition divides it into two parts. Above is the hemicanal of the tensor tympani muscle (semicanalis musculi tensoris tympani), containing the muscle of the same name.
Below is the semicanal of the auditory tube (semicanalis tubae auditivae).
The tensor tympani muscle (half-canal of the tensor tympani muscle) and the auditory tube (half-canal of the auditory tube) pass through the muscular-tubal canal.
Facial canal
The canal of the facial nerve (canalis n. facialis) begins at the bottom of the internal auditory canal and goes forward and laterally to the level of the cleft of the canal of the greater petrosal nerve. Here a bend is formed - the knee of the facial canal (geniculum n. facialis). From the elbow, the channel goes at a right angle laterally and backward along the axis of the pyramid, then changes the horizontal direction to vertical and ends at back wall tympanic cavity with stylomastoid foramen.
The facial canal connects the posterior surface of the pyramid of the temporal bone (internal auditory canal) and the stylomastoid foramen (outer base of the skull).
The facial nerve (VII pair of cranial nerves) passes through the facial canal.
Drum string channel
The canaliculus chordae tympani starts from the facial nerve canal slightly above the stylomastoid foramen and ends in the petrotympanic fissure.
A branch of the facial nerve passes through it - the chorda tympani.
Tympanic canaliculus
The tympanic canaliculus (canaliculus tympanicus) is very narrow; begins in the depths of the stony dimple, goes upward, pierces the lower wall of the tympanic cavity and continues on the labyrinthine wall of this cavity on the surface of the promontory in the form of a groove. Then it pierces the septum of the muscular-tubal canal and ends with the cleft of the canal of the lesser petrosal nerve on the anterior surface of the pyramid.
The tympanic canaliculus contains the tympanic nerve, a branch of the 9th pair of cranial nerves.
Mastoid tubule
The mastoid canal (canaliculus mastoideus) originates in the jugular fossa, crosses the facial canal in its lower part and opens into the tympanomastoid fissure. The auricular branch of the vagus nerve passes through this canaliculus.
The auricular branch of the vagus nerve passes through this canaliculus.
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